Method of manufacturing a wire mesh body



Nov. 28, 1961 a. T. RICHARDS 3,010,195

METHOD OF MANUFACTURING A WIRE MESH BODY Original Filed Dec. 6, 1955 27o l I I I 28 g l i u 32 31 Q nvmvrox 33 1 aamuv 1'. RIOHARDS & 37A's-10min United States Patent 2 Claims. (Cl. 29-419) This inventionrelates to a method of manufacturing a resilient, form-retaining, wiremesh body adapted to serve as a liner for means for supporting conduitlines, for example the fuel lines, oil lines and electric lines of anairplane engine.

These conduit supporting means are commonly known as tube clamps, orclips, and generally include a resilient pad which provides a vibrationreducing suport for the conduit. On aircraft engines, for example, itusually is desired to ground the conduits electrically to the engine orframe on which they are supported and when the resilient pad isnon-metallic it is necessary to provide auxiliary grounding means, whichsometimes is embodied right in the clamp structure. These auxiliarygrounding means add to the cost of the clamp, sometimes make it moredifficult to install the clamp properly on a conduit, and unlessproperly installed do not provide reliable grounding.

It is an object of the present invention to provide an improved methodof manufacturing a wire mesh body to be used as a liner for a clampwhich may be easily and quickly installed on a conduit without danger ofthe pad corners interfering with the installing of the clamp, orbecoming folded back to form a double thickness between the clamp andthe conduit. It also is an object of the invention to provide animproved method of manufacturing a wire mesh body for use as a liner fora tube clamp which furnishes an adequately resilient support and goodelectrical ground for the conduit, which is small in size, which iseconomical to manufacture, and which is suitable for use at hightemperatures. It is a further object of the invention to provide animproved method of manufacturing a compressed, knitted wire fabric padin which there are no wire ends exposed on the surface of the pad. It isstill another object of the invention to provide a method ofmanufacturing a longitudinally split cylindrical metal fabric pad inwhich the opposed longitudinal edges of the split cylinder are formedwith tabs for securing the pad in the clamp and taper back from the tabsto the ends of the cylinder. It also is an object of the invention toprovide a method for manufacturing such a pad from a knitted tubularmetal fabric. Other objects, advantages and improvements of theinvention will become evident or will be pointed out as the descriptionproceeds.

The present application is a division of my application for Tube Clampand Method of Manufacture filed December 6, 1955, Serial No.55 1,406,patented March 22, 1960, Patent No. 2,929,595.

A preferred embodiment of the invention selected for purposes ofillustration and description is shown in the accompanying drawings,wherein:

FIGURE 1 is a perspective view of a tube clamp embodying the presentinvention;

FIGURE 2 is a side elevation of a longitudinally split, cylindrical,metal fabric pad similar to that employed in the tube clamp of FIGURE 1;

FIGURE 3 is an end elevation of the pad shown in FIGURE 2;

FIGURE 4 is an elevation, to enlarged scale, of a length of looselyknitted tubular wire fabric such as may be employed in the manufactureof the pad;

FIGURE 5 is a perspective view illustrating the proice cedure forfolding a. length of relatively large diameter tubular wire fabric inthe production of the longitudinally split cylindrical pad;

FIGURE 6 is a perspective view illustrating the method of folding alength of relatively small diameter tubular Wire fabric in theproduction of the longitudinally split cylindrical pad;

FIGURE 7 is a vertical section through the press mechanism which is usedto compress a folded fabric body into a self-sustaining, longitudinallysplit cylindrical pad; and

FIGURE 8 is a fragmentary perspective view, with parts broken away,enlarged as compared to FIGURE 7, of the dies utilized for forming thelongitudinally split cylind'rical pad.

The tube clamp to which the present invention relates comprises anopenable metal loop adapted to surround a tube or similar'article inspaced relation. In the illustrative embodiment of FIGURE 1 this loop isa flexible metal strap 11 bent to encompass a tube. The straight endportions 12 of the strap 11 are arranged to overlie each other when theloop is clamped about a tube and are provided with registering openingsto receive a bolt or screw to secure the ends together and to secure theloop to a support.

Secured on the inner surface of the bent portion of the loop is a pad 13for gripping a tube when the ends of the loop are brought togetheraround the tube. This pad is generally in the form of a longitudinallysplit, form-retaining cylinder which can be spread open -sufficiently topermit insertion of the tube. If the pad is made of consolidated metalfabric, as it desirably will be, it may be secured to the loop by spotwelds centered lengthwise of the cylinder near its longitudinally splitedges. If the pad is rectangular in shape the unsecured corners or" thepad tend to splay, and when the clamp is positioned around a tube one ormore of the corners may become folded under the rest of the pad andprevent a good uniform grip and contact on the tube.

As may be clearlyseen in FIGURES 1-3, in the present invention theopposed longitudinal edges of the split cylindrical pad 13 are formedwith tabs 14 disposed intermediate the ends of the cylinder, by whichthe pad is secured to the loop 11, for example by spot welds. It hasbeen found that provision of the tabs greatly reduces the tendency ofthe corners of the pad to splay and also reduces the likelihood of anypart of the pad being folded under when the clamp is positioned on atube. The construction is further improved by tapering the opposed edgesof the cylinder back from the tabs to the ends of the cylinder, as shownat 15.

Ordinarily it will be suflicient, and generally preferable, to securethe pad to the loop only by spot welds at the tabs. These welds areindicated at 16, in FIGURE 1.

There are important advantages in making the pad 13 of metal. Metal issuitable for use at very high temperatures and metal eliminates the needfor auxiliary electric grounding means. In order to provide the desiredresiliency and gripping action the metal pad should have a spongycharacter, but still should be firm enough to be self-sustaining inform. There should be no sharp metal edges or wire ends, thisbeing'important from the standpoint of abrasion of the tube and theloop, as .well as from the standpoint of convenience and safety inhandling the pad and the clamp.

According to the present invention the pad 13 is a compressed metalfabric pad manufactured from a length of knitted metal wire tube in sucha manner that no free wire end is exposed on the surface of the finishedpad. The method of making the pad will now be described, reference beingbad particularly to FIGURES 4-8.

FIGURE 4 illustrates, somewhat diagrammatically, a

loosely knitted tubular fabric that has been flattened. This tube may beknitted, for example from stainless steel wire, in long lengths, onconventional wire knitting machines, then flattened and cut to desiredlengths. The knitting should be open or loose, so as to permit adjacentloops to slide on each other and telescope under the pressing operationto be described hereinafter. If compressed in the direction of thelongitudinal axis of the tube, adjacent rows of loops will slide on eachother, whereas compression on the transverse axis will cause adjacentloops within a row to slide on each other and be consolidated.

If knitted tubing of a relatively large diameter is used it may befolded as shown in FIGURE to insure that there will be no wire endexposed on the surface of the finished longitudinally split pad. The cutends 19 of the flattened length 18 of knitted tube are folded togetherabout transverse axes 20 of the flattened tube toward each other, sothat their ends substantially meet, or are separated only by a shortgap. Then the original longitudinal edges of the flattened tube arefolded together about the longitudinal axis 21 of the tube. Thisproduces a multilayer unit of loosely knitted wire fabric in which allwire ends lie in the interior of the unit.

In the event that a knitted tube of relatively small diameter is used itmay be folded as shown in FIGURE 6. The cut ends 23 of the flattenedlength 22 of knitted tube are folded together about transverse axes 24of the flattened tube located approximately of the length of the tubefrom its ends, so that the cut ends substantially meet, or are separatedonly by a short gap, at the longitudinal center of the tube. Then thethus folded ends of the tube are folded together about the centraltransverse axis 25 of the length of tube. This method of folding alsoproduces a multi-layer unit of loosely knit-ted wire fabric in which allof the wire ends lie in the interior of the unit.

The knitted wire fabric unit produced by the folding operation of eitherFIGURE 5 or FIGURE 6 is :1 rectangular body. This unit is rolled into alongitudinally split cylindrical shape, and then compressed andconsolidated by the apparatus shown in FIGURES 7 and 8 to produce afirmly resilient, form-sustaining, longitudinally split cylindrical padsimilar to that illustrated in FIG- URES 2 and 3.

FIGURE 7 shows a press for consolidating the folded multi-layer wirefabric units produced by the folding operation illustrated in FIGURES 5and 6. FiGURE 8 discloses the dies and punch of the press to somewhatlarger scale. Secured on the platen of the press is the tubular outerdie 26. Mounted within the die 26 is the inner die comprising theaxially disposed post 27 and the blade 28. The blade 28 has generally aninverted L- shape, the vertical leg being relatively long. Thetransverse upper end of the blade is secured, for example by a pin 29,in a slot extending across the top of the post 27, and the blade extendsvertically of the post in a continuation of this slot cut in one side ofthe post.

The post 27 is smaller than the bore of the outer die 26 to leave aspace equal to the desired thickness of the pad. Except at the roundedtop of the post, the blade 28 projects radially beyond the surface ofthe post and spans the space to the inner wall of the outer die 26. Theblade separates the edges of the longitudinally split cylindrical padduring the consolidating operation and prevents their entanglement. Theupper end of the blade, where it projects beyond the surface of thepost, may be sharpened as shown at 30 to facilitate separating the edgesof the rolled metal fabric unit as it is inserted between the upperends. of the two dies.

Telescoped between the outer die 26 and the post 27, and normallylocated near the bottom of the outer die, is a sleeve 31 whichcompletely encircles the post. Projecting upwardly from the top edge ofthis sleeve, with sloping surfaces, is a truncated ear 32, the top ofwhich is slotted to form a seat to receive the bottom edge of the blade28. This truncated car 32, in cooperation with the blade 28, serves informing the tabs and the tapering surfaces which extend from the tabs tothe bottom end of the pad.

The ram of the press, movable relative to the platen on suitable guideposts, has secured thereon the punch 33, which is axially aligned withthe outer and inner dies on the platen. The punch 3 is tubular, thelower end thereof being of a thickness to enter between the outer dieand the post of the inner die with a sliding fit. This tubular punch isslotted longitudinally, as shown at 34, the purpose of this slot beingto receive the vertical leg of the blade 28 when the punch is pressedhome into the space between the inner and outer dies. When this occurs,a metal fabric pad which has been inserted between the dies willbecompressed and consolidated along in the direction of the longitudinalaxis of the dies.

The lower end of the punch 33 is provided, on opposite sides of the slot34, with similar ears 35 which match the ear 32 and cooperate therewithin forming the tabs 14 and the tapering edges 15 from the tabs to theends of the cylindrical pad. The wall of the punch may be undercut asshown at 36, either on the inside, the outside, or both, to provideoperating clearance.

The method of producing a clamp pad will next be described. A metalfabric unit produced in accordance with the method illustrated either inFIGURE 5 or FIGURE 6 is rolled into a longitudinally split cylindricalshape and inserted between the inner and outer dies, the longitudinaledges of the cylindrical form being separated by the vertical leg of theblade 28. This metal fabric unit is pushed down between the dies and theram of the press then is lowered to cause the punch 33 to consolidatethe unit in the direction of its longitudinal axis. Radial expansion ofthe unit during such consolidation is limited by the inner and outerdies.

As the punch is lowered into the space between the dies, the rows ofloops in the fabric body slide and telescope on each other if thedirection of compression is in the direction of the originallongitudinal axis of the knitted tube. If the compression is transverseto the original longitudinal axis of the knitted tube, the loops withina row will tend to fold and telescope on each other. The punch alsoproduces some deformation of the original loops where they overlie andcross each other and this results in an interlocking of contiguouslayers causing them to be firmly and resiliently interentangled. Thedegree of consolidation to be performed will depend on the desiredresiliency of the finished pad. The ears 32 and 33 serve to chamfer thecorners of the longitudinally split pad, forming the tabs 14 and thetapered edges 15 extending from the tabs to the ends of the cylinder. 7

Upon completion of the compressing and consolidating step, the ram ofthe press will be raised to withdraw the punch from between the dies.The ejector rod 37, to the upper end of which the inner die is secured,then will be raised until the consolidated pad is exposed above the topof the outer die. The pad then will be stripped from the inner die'andthe ejector rod will be lowered to restore the apparatus to conditionfor receiving another knitted fabric unit.

Where the expression tube clamp is used herein it is not a term oflimitation, but is intended to apply broadly to clamps and clips, or thelike, designed and intended for gripping and holding fuel lines, oillines, electrical conduits, and other elongated cylindrical objects.

It will be understood that the invention herein disclosed may bevariously modified and embodied within the scope of the subjoinedclaims.

I claim:

1. The method of manufacturing a resilient, formretaining wire mesh bodyadapted to serve as a liner for a tube clamp, said method comprising thesteps of knitting a tube of wire, pressing the knitted tube flat,severing a length. of the flattened tube, folding the severed length ofknitted tube into a fiat multi-layer unit with the severed ends locatedinside the unit, rolling the flat multilayer unit into a longitudinalysplit cylindrical shape, consolidating the longitudinally splitcylindrically shaped unit by pressing it in the direction of thelongitudinal axis of the cylinder, while limiting radial expansion ofthe unit, first to cause the loops of the knitted structure to slide oneach other, and then under suflicient pressure to cause contiguouslayers to become firmly and resiliently interentangled in longitudinallysplit cylindrical form and, while so consolidating the longitudinallysplit cylindrically shaped unit longitudinally, simultaneouslyconsolidating the corners of the longitudinal split in a circumferentialdirection to chamfer the said corners.

2. The method of manufacturing a resilient, form-retaining Wire meshbody adapted to serve as a liner for a tube clamp, said methodcomprising the steps of knitting a tube of wire, pressing the knittedtube flat, severing a length of the flattened tube, folding the severedlength of knitted tube into a flat multi-layer unit with the severedends located inside the unit, rolling the flat multi-layer unit into alongitudinally split cylindrical shape, consolidating the longitudinallysplit cylindrically shaped unit by pressing it in the direction of thelongitudinal axis of the cylinder, while limiting radial expansion ofthe unit, first to cause the loops of the knitted structure to slide oneach other, and then under sufiicient pressure to cause contiguouslayers to become firmly and resiliently interentangled in longitudinallysplit cylindrical form and, while so consolidating the longitudinallysplit cylindrically shaped unit longitudinally, simultaneouslyconsolidating the corners of the longitudinal split in a circumferentialdirection to form tabs intermediate the ends of the cylinder andtapering surfaces from the tabs to the ends of the cylinder.

References Cited in the file of this patent UNITED STATES PATENTS2,439,424 Goodloe :Apr. 13, 1948 2,724,176 White Nov. 22, 1955 2,755,079York July 17, 1956 2,857,610 Rympalski Oct. 28, 1958

